Abstract
Purpose.
The aim of this study was to assess the effectiveness of 4D sonography (US) to guide amniocentesis when compared with standard 2D US, and to evaluate the impact this new method may have on needle placement, the number of needle insertions performed, and duration of the procedure.
Methods.
One hundred routine consecutive unselected amniocenteses were performed with 4D USโguided technique and compared with 100 standard 2D USโguided amniocenteses. All procedures were performed by trainees in maternalโfetal medicine under the supervision of expert sonographers.
Results.
There were no significant statistical differences between 4D and 2D USโguided amniocenteses. The procedure time was longer with the 4D US guidance than with the 2D US guidance, but this difference was not statistically significant. A 2nd needle insertion was necessary in two cases with 4D US guidance and in three cases with 2D US guidance. A better visualization of the needle tip was observed in both techniques when a 20โgauge needle was used.
Conclusion.
The 4D US, which allows the needle tip to be displayed in real time in three orthogonal planes simultaneously, thus providing reassurance that no fetal parts are in the needle path, did not offer any advantage over 2D US in guiding routine midtrimester amniocentesis and this new modality has not yet proved effective in reducing the number ofneedle insertions. ยฉ 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009